DataGridView select first column header cell if SelectionMode = DataGridViewSelectionMode.FullRowSelect

[altbodhi]

.NET 10

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>WinExe</OutputType>
    <TargetFramework>net10.0-windows</TargetFramework>
    <UseWindowsForms>true</UseWindowsForms>
  </PropertyGroup>

  <ItemGroup>
    <Import Include="System.Data" />
    <Import Include="System.Drawing" />
    <Import Include="System.Windows.Forms" />
  </ItemGroup>
  
  <ItemGroup>
    <Compile Include="Program.fs" />
  </ItemGroup>
</Project>

open System.Windows.Forms

type App() as x =
    class
        inherit ApplicationContext()

        do
            x.MainForm <- new Form(Text = "App v1", Width = 300, Height = 200)

            let dg = new DataGridView(SelectionMode = DataGridViewSelectionMode.FullRowSelect)

            x.MainForm.Controls.Add dg
            dg.Dock <- DockStyle.Fill

            let addCol name =
                dg.Columns.Add(new DataGridViewColumn(HeaderText = name, CellTemplate = new DataGridViewTextBoxCell()))
                |> ignore

            addCol "Id"
            addCol "Name"

            dg.Rows.Add([| box 1; box "Alice" |]) |> ignore
            dg.Rows.Add([| box 2; box "Bob" |]) |> ignore
            dg.Rows.Add([| box 3; box "Rob" |]) |> ignore

        static member Run() = Application.Run(new App())
    end

App.Run()

Did it work in .NET Framework?

Yes

Did it work in any of the earlier releases of .NET Core or .NET 5+?

no

Issue description

With free or object source and SelectionMode = DataGridViewSelectionMode.FullRowSelect first column header cell
selected at startup.
I did not check but found example worked without issue if source DataTable.

Steps to reproduce

Make WinForms App
Add DataGridView with one or more columns
add object datasource or fill rows by hands and test.

[altbodhi]

But
dg.Columns.Item(0).HeaderCell.Selected <- false
produced exception: 'Property Selected of a DataGridViewHeaderCell cell cannot be set.'

[altbodhi]

No, with DataTable the same as:

open System.Windows.Forms
open System.Data

type App() as x =
    class
        inherit ApplicationContext()

        do
            x.MainForm <- new Form(Text = "App v1", Width = 300, Height = 200)

            let table = new DataTable()
            table.Columns.Add(new DataColumn("Id"))
            table.Columns.Add(new DataColumn("Name"))
            table.Rows.Add([| box 1; box "Alice" |]) |> ignore
            table.Rows.Add([| box 2; box "Bob" |]) |> ignore
            table.Rows.Add([| box 3; box "Rob" |]) |> ignore

            let dg =
                new DataGridView(DataSource = table, SelectionMode = DataGridViewSelectionMode.FullRowSelect)

            x.MainForm.Controls.Add dg
            dg.Dock <- DockStyle.Fill

        static member Run() = Application.Run(new App())
    end

App.Run()

[LeafShi1]

This behavior is caused by the DataBinding lifecycle of DataGridView.

If SelectionMode is set before assigning DataSource, the binding process may reapply selection and produce unexpected visual states (such as a header cell appearing selected).

Setting SelectionMode after DataSource, or clearing selection in DataBindingComplete, ensures the final selection state is consistent.

Workarounds:

• Set SelectionMode after DataSource
• Or call ClearSelection() in DataBindingComplete

[LeafShi1]

I will close this issue, please let us know if you have any further questions.

[altbodhi]

I try first advice but it not working пн, 15 июн. 2026 г., 15:59 Leaf Shi ***@***.***>:

…

*LeafShi1* left a comment (dotnet/winforms#14649) <#14649 (comment)> I will close this issue, please let us know if you have any further questions. — Reply to this email directly, view it on GitHub <#14649?email_source=notifications&email_token=AFZYZQP2RGIWAZHVSPNLLPL4763I3A5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTINZQGYZDEOJXGU4KM4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2KYZTPN52GK4S7MNWGSY3L#issuecomment-4706229758>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AFZYZQIIMKM3VQTIN3JKS734763I3AVCNFSNUABFKJSXA33TNF2G64TZHMYTKMZXGEYTQMZQHNEXG43VMU5TINRVHAYDKNJVGI32C5QC> . Triage notifications, keep track of coding agent tasks and review pull requests on the go with GitHub Mobile for iOS <https://github.com/notifications/mobile/ios/AFZYZQPYYRP342PMPZPF4YD4763I3A5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTINZQGYZDEOJXGU4KM4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2KUZTPN52GK4S7NFXXG> and Android <https://github.com/notifications/mobile/android/AFZYZQOQYSHUPBTMF4H4PJ34763I3A5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTINZQGYZDEOJXGU4KM4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2K4ZTPN52GK4S7MFXGI4TPNFSA>. Download it today! You are receiving this because you authored the thread.Message ID: ***@***.***>

[LeafShi1]

I try first advice but it not working

Is it completely useless? What about the second option?

Recording.2026-06-16.085546.mp4

[altbodhi]

It works! вт, 16 июн. 2026 г. в 07:58, Leaf Shi ***@***.***>:

…

*LeafShi1* left a comment (dotnet/winforms#14649) <#14649 (comment)> I try first advice but it not working Is it completely useless? What about the second option? https://github.com/user-attachments/assets/5f3a1c64-1b60-47af-8ebd-5fe6b57b3ece — Reply to this email directly, view it on GitHub <#14649?email_source=notifications&email_token=AFZYZQK3ZZ65GOFZ2QP52JD5ACLTPA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTINZRGM4DONBYGU4KM4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2KYZTPN52GK4S7MNWGSY3L#issuecomment-4713874858>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AFZYZQPJNSTFAWXYVSSPAET5ACLTPAVCNFSNUABFKJSXA33TNF2G64TZHMYTKMZXGEYTQMZQHNEXG43VMU5TINRVHAYDKNJVGI32C5QC> . Triage notifications, keep track of coding agent tasks and review pull requests on the go with GitHub Mobile for iOS <https://github.com/notifications/mobile/ios/AFZYZQOJLVSHVD7AMR7D6ST5ACLTPA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTINZRGM4DONBYGU4KM4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2KUZTPN52GK4S7NFXXG> and Android <https://github.com/notifications/mobile/android/AFZYZQKDC52UEV7NRLOWRND5ACLTPA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTINZRGM4DONBYGU4KM4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2K4ZTPN52GK4S7MFXGI4TPNFSA>. Download it today! You are receiving this because you authored the thread.Message ID: ***@***.***>